I was thinking more in terms of getting overheated. Perspiration helps to keep our body temperature regulated and if you stop perspiring, you are more likely to suffer from heat exhaustion or heat stroke. The marine lab I work at sends us messages every summer to remind to drink water while we are working out on the boats in the hot sun. Don't know about the always being cold thing. Are you anemic?
My transplant center told me 64 ounces of fluid a day. However, the way they have always judged whether I was hydrated enough was by my BUN. Consequently, whenever my BUN is higher my creatinine is higher as well. Also, it has varied between medications. I have never really been able to drink 64ounces a day, but have found that with cyclosporine and prograf I needed to drink more to keep my BUN down, whereas with rapamune I haven't been drinking very much each day and my BUN has been the lowest it has ever been since my transplant.